Effect of breeder age and breeding season on egg production and incubation in farmed ostriches

(1) This research was carried out to investigate changes in egg production and hatchability as influenced by age and breeding season of 10 trios (two females, one male) of ostrich (Struthio camellus) during 1998 to 2002. (2) Breeding season affected number of eggs laid per female per season, average egg weight, length of laying period and clutch sequence. (3) The number of eggs laid per female per season was 25 in the first breeding season and 57 by the fifth breeding season. The laying period lasted 169 d in the first season whereas it was 210 d by the fifth season. The breeding season became longer year by year. (4) The number of clutches was two in the first season, three in the second and 4 in the later breeding seasons: the mean interval between cycles was 9 to 10.6 d and the mean number of eggs in one cycle varied from 12 to 14.4. (5) The breeding season affected the hatchability of fertile eggs, chick weight at hatching, hatchability of total eggs, fertility, malpositioned embryos, deformed chicks and assisted chicks during hatching. The first 4 variables increased and the last three decreased, with each breeding season. (6) Weight loss of eggs and length of incubation were unaffected by the breeding season. Hatchability which was 64.3% in the first season increased progressively and reached 73.1% in the fifth breeding season.     

Blood acid-base and plasma electrolyte values in healthy ostriches: The effect of age and sex

The effect of age and sex on blood acid-base and plasma electrolyte values was determined in venous blood samples from 45 clinically healthy ostriches (Struthio camelus) from 26 days to 6 years of age. Animals were divided by age into four groups and the group of adults was divided by sex into two subgroups. Blood samples were collected without sedation. There was a significant (P < 0.05) age difference in blood values of base excess (BE), plasma , total CO₂ (TCO₂), Na⁺, K⁺, Cl⁻ and anion gap (AG). The highest plasma concentrations of Na⁺, Cl⁻ and value of AG were found in adult ostriches with a steady decrease to chicks. A significant (P < 0.05) sex difference in adult animals with higher blood pH, lower blood values of pCO₂, BE, plasma concentrations of , TCO₂ and K⁺ was found in females. We concluded that blood acid-base values and plasma electrolyte concentrations in ostriches are affected by age and sex.     

补饲青绿饲料对不同性别肉仔鸡屠宰品质的影响

试验旨在探讨饲喂全价基础日粮的基础上补饲青绿饲料对不同性别肉仔鸡屠宰品质的影响。选择1日龄健康AA肉鸡360只(公母各半),根据不同性别随机分成4组,每组3个重复,每重复30只。分别设为Ⅰ♂、Ⅱ♂、Ⅰ♀、Ⅱ♀组。Ⅰ♂和Ⅰ♀为对照组,饲喂全价基础日粮,Ⅱ♂和Ⅱ♀为试验组,全期补饲新鲜青绿饲料。分别于第14、28、42日龄(d)时取样进行屠宰品质分析。结果表明:①各试验日龄公鸡的体重高于母鸡(P<0.05或<0.01);42日龄时公鸡的屠宰率和半净膛率高于母鸡(P<0.05),腹脂率低于母鸡(P<0.05)。②补饲青绿饲料能显著提高肉仔鸡胸肌率(P<0.05)和降低腹脂率(P<0.05),42日龄时公鸡和母鸡的胸肌率分别提高了14.9%和16.4%,腹脂率分别降低了20.8%和22.2%。③补饲青绿饲料对肉仔鸡屠宰率、半净膛率、全净膛率和腿肌率无显著影响。④总体上补饲青绿饲料对母鸡屠宰品质的影响作用更大。     

Effect of cottonseed oilcake as a protein source on production of breeding ostriches

1. South Africa currently produces 70% of the world’s ostrich products. The profit margin of South African producers from the sale of ostrich meat, leather and feathers currently stands at 20%, 65% and 15%, respectively.

2. Local producers want to increase the production of ostrich products but keep production costs as low as possible. Maintaining optimal nutrition of breeding stock is necessary to increase the production of ostrich chicks, thereby decreasing the fixed costs per chick.

3. This research examined the impact on ostrich reproduction of replacing soya oilcake (SOC) as a protein supplement with cheaper cottonseed oilcake (CSOC). Although there are no data available on the impact of CSOC feed on ostrich reproduction, it is well known that gossypol, a naturally occurring toxin in cotton plants, negatively affects male reproduction in other monogastric species and that it may also reduce appetite.

4. Ninety-six breeding ostrich pairs were divided into two groups to compare the effects of diet (CSOC and SOC) during the breeding season on ostrich-breeding parameters. The replacement of SOC with CSOC had no significant effect on the number of total eggs produced (47.8 ± 5.3 versus 48.3 ± 5.1 per breeding pair, respectively) or infertile eggs (31.5 ± 3.9 versus 38.0 ± 5.2, respectively). Also, the number of dead-in-shell chicks did not differ significantly between groups (20.2 ± 3.3 versus 26.8 ± 3.8, respectively).

5. Even though none of these breeding parameters differed, the replacement of SOC with CSOC in the diets of breeding birds led to significantly more chicks hatching per hen from breeding birds fed on the SOC (36.1 ± 4.8) than the CSOC diet (17.2 ± 3.8).

6. Although it would thus seem that feeding breeding ostriches CSOC instead of SOC as a protein supplement will have a detrimental effect on chick production, more data are required to deliver a definitive answer.

     

Molecular characterization of H5N2 avian influenza viruses isolated from South African ostriches in 2006

Highly pathogenic avian influenza (HPAI) H5N2 reemerged in ostriches in South Africa during 2006, and a low-pathogenic AI H5N2 virus was also isolated. Molecular and phylogenetic characterization was performed to determine whether the outbreak strains were genetically derived from the supposedly eradicated Eastern Cape ostrich outbreak HPAI H5N2 strain of 2004. It was demonstrated that although the 2004 and 2006 South African H5N2 strains shared a common ancestor, the two outbreaks were not related. Not only were extensive reassortments with wild bird viruses involved in the evolution of the 2006 strains, but the precursor HA molecule HA0 cleavage site sequence of the 2006 HPAI H5N2 virus also contained fewer basic amino-acid insertions. Multiple transmission events occurred from wild birds to ostriches in 2006, and it appears that a reservoir of H5N2 with pathogenic potential for poultry is established in the South African wild duck population.     

Growth and sensory characteristics of organically reared broilers differing in strain,sex and age at slaughter

Abstract

The effects of strain, sex and age on live weight, slaughter weight and sensory characteristics of organically reared broilers in orchards are presented. A total of 450 broilers of three different strains (I 657, Light Sussex, New Hampshire) were reared in an organic research orchard. Half of each strain was slaughtered at 91 days and the other half at 120 days. All broilers were weighed and a clinical welfare assessment was made at slaughter. A trained sensory panel evaluated the breast meat in relation to flavour, smell and texture characteristics defined by the panel. At both 91 and 120 days of age the commercial breed I 657 was significantly heavier than the slower growing strains. Males were significantly heavier than the females across strains. Weight ratios between males and females were nearly the same at both slaughter ages in I 657, whereas weight ratios increased significantly at 120 days in Light Sussex and New Hampshire. No overall effect of strain was found on the flavour and smell of the breast meat. However, the age-related changes in tenderness and toughness differed significantly between strains, since the commercial strain tended towards a tougher and less tender consistency with age, whereas the opposite was the case for the slower growing pure breeds. The positive flavour of salt was significantly improved at 120 days across strains with females having a saltier flavour than the males with age. The positive flavour of sweet corn was improved in the meat from the males, whereas the positive smell of sweet corn was significantly improved in both males and females. No negative effects of age were found.

In conclusion, broilers were tastier when slaughtered at 120 days compared with 91 days. The development in meat tenderness was related to strain, and weights at slaughter were related to both strain and sex.     

Effect of age at slaughter on carcass traits and meat quality of Italian heavy pigs

Barrows and gilts (n = 128) from four breed crosses were used to investigate the effect of age at slaughter on carcass traits, proteolytic enzyme activity, and meat and fat quality. Pigs were blocked by breed cross into four blocks, and within blocks, one pen (eight barrows and eight gilts) was assigned randomly to be slaughtered at either 8 or 10 mo of age. Pigs were fed a corn-barley-soybean meal finisher diet from 104 +/- 2.5 d of age (37.7 +/- 0.33 kg BW) to the appropriate slaughter age. Carcasses from older (10 mo) pigs had lower (P < 0.01) muscularity indexes and lean cut yields than those of younger (8 mo) pigs, but dressing percentage and longissimus muscle area increased (P < 0.01) with age. Older pigs produced a redder (P < 0.01) and darker (P < 0.05) semimembranosus, with lower (P < 0.01) ultimate pH and cathepsin B and B + L activities, as well as higher (P < 0.01) aminopeptidase hydrolyzing activity than younger pigs. Moreover, the longissimus muscle of pigs slaughtered at 10 mo of age had lower (P < 0.01) drip and cooking loss percentages than that from pigs slaughtered at 8 mo of age. Ham subcutaneous fat from 10-mo-old pigs had greater (P < 0.05) percentages of oleic acid and lower (P < 0.01) proportions of moisture, linoleic, and linolenic acids than subcutaneous fat from pigs slaughtered at 8 mo of age. Results from this study indicate that fresh hams from pigs slaughtered at 10 mo of age would be more suitable for the production of high-quality, Italian, dry-cured hams.     

菜籽粕对蛋鸡生产性能与屠宰性能的影响

选择756羽开产50周左右的罗曼蛋鸡,随机均分7组,对照组使用船牌公司配合饲料,试验1～6组分别添加7.5%、8.0%、8.5%、9.0%、9.5%和10.0%的双低菜籽粕,进行饲养试验与生长测定,探索改善蛋鸡生产性能与蛋品质含量的双低菜籽饼(粕)最佳使用量,为充分利用贵州省丰富的菜籽饼(粕)资源奠定基础。结果显示,日粮中添加10%以下的双低菜籽粕对蛋鸡的采食、生长性能、蛋的性状均无不良影响,反而会提高蛋鸡的产蛋率,增加蛋重、降低料蛋比,其中试验4组的料蛋比(2.30)最低,平均日采食量也较低,平均蛋重较重,产蛋率也偏高。研究表明,蛋鸡日粮中添加9.0%双低菜籽粕对提高蛋鸡生长性能与产蛋性能具有良好效果。     

Effect of age and sex on the prevalence of intestinal parasitism in cats

The effects of age, sex, and neutering on the prevalence of feline intestinal parasitism were evaluated by fecal examination of 1,294 cats admitted to the University of Missouri Veterinary Teaching Hospital for the 3-year period, 1974 to 1976. Approximately 37% of the cats examined had 1 or more parasite species. Ascarids were the most commonly encountered parasites (24.4%), with coccidia (6.7%), hookworms (6.4%), tapeworms (5.2%), and trichurids (2.6%) being less frequently observed. Most parasitisms were monospecific. Considering age categories from birth to 5 years, patent ascarid infections were less prevalent in cats greater than 6 months old, whereas hookworm infections were most prevalent in cats 1 to 5 years old; trichurids (whipworms and capillarids) were most often found in cats greater than 6 months old; and coccidia were found with uniform frequency in cats of all age categories. Sex seemed to have no effect on prevalence of parasitism, and the only effect of neutering was on the occurrence of ascarid infection, with spayed females having a prevalance of 14.3%, castrated males, 17.8%, and their intact counterparts, 26%.     

不同锌源及其水平对桃源鸡生产性能及屠宰性能的影响

选用360只桃源鸡以研究不同锌源、锌水平日粮对桃源鸡生产性能和屠宰性能的影响。试验采用2因素3水平完全随机试验设计,2种锌源分别为羟基蛋氨酸锌、氧化锌,添加水平分别为:30 mg/kg、60 mg/kg、90 mg/kg;将桃源鸡随机分为6个处理组,每个处理组下设3个重复,每个重复20只鸡,分两阶段饲养:3~48日龄、48~93日龄。每个试验期结束时进行生产性能指标的测定;试验结束时每组各选体重相近的肉鸡6羽,共36羽,禁食12 h,进行屠宰试验。研究结果表明:①生产性能:锌源的添加能提高桃源鸡的日增重,且随锌源的添加呈上升趋势(P>0.05);锌的添加降低桃源鸡料肉比,除氧化锌低添加水平(30 mg/kg)外,试验前期和试验全期锌的添加能显著降低桃源鸡的料肉比(P<0.05),试验后期差异不显著(P>0.05);②屠宰性能:锌源添加时桃源鸡的屠宰率、半净膛率、全净膛率、胸肌率及腿肌率都很接近,统计分析各处理组间试验动物的屠宰性能差异不显著(P>0.05)。     

Effect of temperature and rainfall on the distribution of the South African shelduck Tadorna cana

The distribution of the South African shelduck Tadorna cana was mapped and related to temperature and rainfall. A multiple regression analysis based on quantified spatial abundance (the number of sixteenth degree squares recorded with shelduck in a degree square), mean annual rainfall, mean annual temperature and mean temperature of the coldest (July) and hottest (January) months indicated a significant (P < 0,001) negative linear relation between shelduck distribution and temperature, but no significant (P > 0,05) relation with rainfall. Mean annual rainfall in excess of 600 mm is however suggested to bring about unfavourable habitat within temperate southern Africa. The hypotheses formulated on the environmental relations of shelduck distribution are compared with habitat preference, breeding season, nest sites and feeding behaviour.     

Heat production and dissipation in a South African diurnal murid Lemniscomys griselda

Heat production measured as oxygen consumption (V_O2 and heat dissipation calculated as the means of the overall thermal conductance were studied in a South African diurnal murid Lemniscomys griselda. This species maintains its body temperature (T_b) well at around 36,5 ± 1,0 °C over ambient temperatures (T_a) ranging between 5 and 34 °C. The thermoneutral zone lies between T _a = 30-34 °C. When exposed to temperatures below the low critical point L. griselda at rest conforms to Newton's law of cooling. Non-shivering thermo- genesis (NST) was studied as a response to an injection of noradrenaline (sc). Following the administration of 1,5 mg noradrenaline per kg body mass to an anaesthetized animal, an increase of 329% in VO₂ was recorded. The distribution pattern of L. griselda in comparison with that of Rhabdomys pumilio, the more common diurnal murid species in South Africa, is discussed.     

Effect of age and sex on the chemical composition of edible offal and blood from broilers

1. The effects of age and sex on the proximate composition and inorganic constituents in edible offal and whole blood from a commercial British broiler chicken strain were studied.

2. Although the protein content of all tissues varied with age, the only statistically significant effect was on the level of protein in the gizzard.

3. The moisture content of the gizzard was significantly affected by age and blood by age and sex.

4. The fat content of the gizzard was significantly affected by age, as was the effect of sex on the fat content of blood.

5. The ash contents of heart and gizzard were significantly affected by age.

6. The phosphorus contents of the gizzard, heart and liver were significantly affected by age, as were the chloride content of heart and the calcium content of the liver. Blood potassium was significantly affected by sex. Fluctuations in the contents of other elements are discussed.

7. The variability in organ composition is discussed with respect to the degree of trimming and preparation of the samples.     

饲料中添加硒制剂对幼龄鸵鸟生长发育的影响

选取10日龄雏鸵鸟123只，随机分成试验1、2、3组和对照组，在试验组的饲料中添加不同浓度的硒制剂，进行为期75d的饲养试验。结果表明：试验3组在增重和饲料报酬以及成活率均优于对照组和试验1、2组。且差异极显著（P＜0．01）和差异显著，经血液检测COT、LDH、CK值以试验3组最理想。与报道正常值相一致，表明在圈养人工投喂精、青饲料条件下，饲料中硒浓度以0．3ppm为最合适。     

Effect of feeding methods and age at slaughter on growth performances and carcass characteristics of entire young male goats

Thirty six Alpine male kids were divided into six groups. The first two groups received only milk replacer and were slaughtered at 16 kg (group L16) or at 22 kg (group L22), the next two groups were offered milk replacer + concentrates and slaughtered at 22 kg (group C22) or at 28 kg (group C28) and the last groups were subjected to stepwise weaning followed by feeding with maize wafers + concentrates and slaughtered at 28 kg (group M28) or at 34 kg (group M34).The daily mean gain (g/day), carcass weight (kg) and dressing percentage (%) were 209, 7.50 and 52.8 respectively for group L16; 219, 10.34 and 53.4 for group L22; 241, 9.82 and 53.9 for group C22; 208, 11.48 and 51.2 for group C28; 172, 10.31 and 51.0 for group M28; and 176, 12.86 and 52.0 for group M34.Thus, with this type of animal the daily mean gain may definitely exceed 200 g/day, but weaning significantly reduces this gain.Carcass conformation was not very favourable. As compared to lambs, kid carcasses are characterized by a very poor proportion of fat, in particular subcutaneous fat, and by a slightly lower muscle to bone ratio.The different feeding methods are discussed in relation to slaughter weight and feeding costs. The use of milk replacer only seems to be satisfactory up to a live weight of about 18 kg; thereafter, addition of concentrates to the diet is preferable. For slaughter weights above 25 kg, it is economically better to wean the kids even if the growth rate is reduced.     

Influence of age, sex, and production class on liver zinc concentration in calves.

Determination of zinc concentrations in the liver of calves and young stock is commonly requested by practitioners and nutritionists to assess whether they receive an appropriate amount of zinc in their diet. However, interpretation of liver zinc concentrations is currently based on information reported for adult cattle for which the health status was unknown and irrespective of production class, sex, and age. A retrospective study of necropsy reports was undertaken to assess the relationships between liver zinc concentrations and age, sex, and production class for calves that did not have a history compatible with zinc toxicosis or zinc deficiency. Results of a generalized least squares, polynomial regression analysis of 474 records found that zinc concentration was not affected by sex (P = 0.29) or production class (P = 0.50). Zinc concentration was significantly associated with linear (P < 0.00001) and nonlinear (quadratic, P = 0.0039) functions of age (r2 = 0.1503), where the concentration decreased from 93 mg/kg wet weight at 30 days of age to 57 mg/kg wet weight at 9 months of age, after which it began to increase. The age-specific 95% confidence limits of the mean concentration for a group of calves and the 95% prediction limits of a single concentration value for an individual animal estimated in this study suggest reconsideration of the recommended limits for liver zinc concentration in calves. As a consequence of the significant influence of age on liver zinc concentration of calves presumably not experiencing zinc toxicosis or deficiency, diagnosis of zinc imbalances based on liver zinc concentration needs to consider age as a diagnostic covariate.     

The effect of dietary energy and protein levels on production in breeding female ostriches

1. In a study spanning two breeding seasons, we assessed the effect of different dietary energy and protein levels on body mass, body condition, and egg production of female ostriches. 2. During the first breeding season, groups were given diets with energy concentrations of 8.5, 9.5 and 10.5 MJ/kg dry mass (DM) metabolisable energy (ME) and protein concentrations of 135, 150 and 165 g/kg. In the second breeding season, groups were given diets with ME of 7.5, 8.5 and 9.5 MJ/kg and protein contents of 105, 120 and 135 g/kg. 3. Body mass of birds on diets of 7.5 and 8.5 MJ/kg ME decreased significantly in the course of the breeding season compared with birds fed on diets with higher energy contents and body measurements decreased, suggesting a loss of body condition. 4. Females fed on diets containing only 7.5 MJ/kg ME produced significantly fewer eggs at significantly longer intervals, resulting in fewer chicks hatched. 5. There was no significant difference in egg mass, initial chick mass, chick survival to one month of age and body mass of chicks at one month. 6. Dietary protein concentrations had no effect on egg production, egg mass, hatchability, initial chick mass, chick survival or chick mass at one month old. 7. The female ostriches regained their original body mass during the 4-month rest period between breeding seasons, but significant differences in some parameters during the second breeding season suggest that they may not have fully recovered their body condition. 8. A dietary energy content of 7.5 MJ/kg proved to have an adverse effect on egg production by breeding female ostriches, and it may be concluded from this study that a diet containing 8.5 MJ ME/kg DM and 105 g/kg protein should be regarded as the minimum that can be used for breeding female ostriches without compromising egg production.     

Effect of separate transport, lairage, and slaughter on occurrence of Salmonella typhimurium on slaughter carcasses

The study aimed to reduce cross-contamination between finishers from Salmonella-positive and Salmonella-negative herds during transport, lairage, and slaughter, thereby reducing the prevalence of Salmonella Typhimurium on slaughter carcasses. In Phase 1 of the study, pigs from Salmonella-negative herds were kept in lairage for 2-4 hours either in clean pens (intervention group) or pens contaminated with Salmonella-infected faeces (control group). All pigs were slaughtered on the same slaughterline, and carcass swabs 24 hours after slaughter revealed a low degree of cross-contamination in the pens: there was no difference in Salmonella-positive carcasses between intervention (1.7%) and control groups (0.8%). In Phase 2, control pigs from Salmonella-negative herds were mixed with pigs from Salmonella-positive herds during lairage for 2-4 hours, while the intervention group still consisted of pigs from Salmonella-negative herds. All pigs were slaughtered on the same line: first intervention, then control. Carcass swabs taken 24 hours after slaughter failed to show a reduction in Salmonella-positive carcasses in the intervention group (4.5%) compared with the originally Salmonella-negative pigs in the control group (3.6%). In pigs from Salmonella-positive herds the occurrence of Salmonella was substantially higher at 10.4%. When the results were corrected for 6 carcass samples found positive with S. Heidelberg on the same day, which was attributed to a transient hygiene failure, only 2.2% of the carcasses in the intervention group were Salmonella-positive. We conclude that even though cross-contamination occurs in the abattoir pens, its importance on the slaughter line may be greater. However, the final results of this study should be awaited to conclude whether separate slaughter of pigs from Salmonella-positive and Salmonella-negative herds should be recommended.